Conventionally, an aerosol can comprises of a cylindrical-shaped gas container provided with, on one of its faces, referred to as the upper portion and closing its cylindrical-shaped casing, a retainer whereon a valve is attached. This valve allows the exiting of the aerosol pushed by the propellant gas contained under pressure when the latter is maintained pressed. This type of can may also be used as a compressed gas container.
This known device has the disadvantage of not being able to obtain a constant rate of outflow since the latter varies according to the internal pressure of the gas contained in the can.
It is certainly also known to be able to regulate the pressure and therefore the rate of a flow of gas at the outflow of a pressurized container using a regulator taking into account the exterior or ambient pressure and the variations of pressure of the source of gas.
Such a regulator generally comprises a valve pushed back into a closed position against a seating and controlling the passage of the flow of gas from the high pressure portion to a low pressure chamber, a control member of the valve under the dependency of a membrane or piston closing on one side of the low pressure chamber, a retaining means or spring butting against the other side of the membrane or piston, and a means of adjusting the retaining means.
Many devices have been developed to adapt such regulating systems to aerosol containers, in order to limit the disadvantage of providing only a rate of outflow that varies with the internal pressure of the compressed gas in the container and that therefore of course goes down as it is used.
French Patent Application No. FR 2774077 of the LOREAL company discloses an internal modification of the valve itself of the aerosol container in order to correct the output pressure of the fluid but without changing the operating principle of the aerosol itself, i.e., requiring a manual pressing on the dispensing button and comprising multiple parts forming a rather complex device.
Likewise, French Patent Application No. FR 2702465 to LE COFFRE and TOURNASSAT is discloses a device added to the aerosol container without modifying the latter and creating a loss of head through a very long channel of small section, in order to obtain a low rate but which is not constant for aerosol containers containing non-liquefied gas, and of which the realization is also complex.
Other devices of the same or similar type, either do not satisfy, as hereinabove, a genuine regulation of a gas flow at a constant rate under low pressure, such as is necessary for the calibration of analyzers, or they still require the manual intervention of an operator in order to maintain a control button pressed releasing the gas to be dispensed, or they are for the most part rather complex to realize, requiring special machine toolings in order to have the associated seatings and valves, as well as various channels connecting the upper pressure and low pressure chambers of the regulating device that one wants to obtain.
Indeed, the maintaining of a manual pressing is not compatible with the necessity to diffuse a gas continuously (even during several days without stopping) for applications, such as by way of example the diffusion of scents or pheromones, or for the stimulation of rubber trees by ethylene gas which allows for increased production of latex with a dispenser of ethylene at a very low constant continuous rate, and attached to each tree.
Therefore, there remains a need for a pressure maintaining device, at the outflow of an existing valve of an aerosol container, at a constant value that is defined by the user and to diffuse as such the gas contained in the latter at a constant rate, and continuously without manual actuation other than that of putting it into operation and therefore not necessarily maintained on the device during the entire dispensing of gas, the device having to be as simple as possible to realize, requiring less parts than the known regulators, easy to set up and utilizing existing technologies to the fullest that are already developed for high-volume applications.